The present invention is concerned with an electronic solid state digital differential pressure gage system for directly displaying the pressure loss across a particular component at different flow rates; or to determine the pressure rise in a system caused by a pump. The invention is also concerned with an electronic solid state digital flow meter.
The pressure gage system of the invention finds particular utility during the development and manufacture of hydraulic components, such as valves, couplings, fittings, pressure regulators, flow regulators, pumps and the like. The system of the invention is used to measure the fluid flow versus pressure drop characteristics of such components at different flow rates in order to determine whether the particular component meets required performance standards and also to supply the user with necessary data for the design of the system.
The prior art systems for measuring pressure loss across a particular component at different flow rates usually includes Bourdon tube gages and mercury manometers. However, such prior art measuring systems are bulky and relatively inaccurate. Data collection in such prior art systems requires the operator to move from instrument to instrument to acquire data for each flow setting. Moreover, Bourdon tube gages are prone to vibration and often require damping. In addition, mercury manometers have a tendency to oscillate. Also, the readings from the gages and manometer generally require conversion to more convenient units.
The prior art systems are also subject to additional drawbacks. For example, the Bourdon tube gage requires interpolation of the gage marks; and the mercury manometer requires reading the cusp of a meniscus which many times is too dirty to accurately delineate. Some digital turbine flow meters require long waiting periods for the turbine speed to stabilize before readings can be taken. Venturi flow meters that use mercury manometers to read die pressure difference face the same problems discussed above.
An important element in the system of the invention is the pressure transducer which, for example, may be a silicon micro-machined solid state device that may be mounted on a printed circuit board. The system of the invention in the embodiment to be described incorporates a solid state pressure meter with a liquid crystal display device which is similar in some respects to the pressure meter described in U.S. Pat. No. 4,850,228.
Accordingly, an objective of the present invention is to provide a relatively inexpensive solid state digital pressure gage system which is easy to operate and which overcomes the problems inherent in the prior art systems.
The system of the invention is one in which the pressure drops of the various components being measured are directly displayed, for example, on the liquid crystal display device in any desired measurement unit.